初始提交: UE5.3项目基础框架

Plugins/CesiumForUnreal/Source/CesiumRuntime/Private/CesiumPrimitive.h

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+// Copyright 2020-2024 CesiumGS, Inc. and Contributors
+
+#pragma once
+
+#include "Cesium3DTileset.h"
+#include "CesiumEncodedFeaturesMetadata.h"
+#include "CesiumEncodedMetadataUtility.h"
+#include "CesiumMetadataPrimitive.h"
+#include "CesiumPrimitiveFeatures.h"
+#include "CesiumPrimitiveMetadata.h"
+#include "CesiumRasterOverlays.h"
+#include <CesiumGltf/AccessorUtility.h>
+#include <cstdint>
+#include <glm/mat4x4.hpp>
+#include <optional>
+#include <unordered_map>
+
+#include "CesiumPrimitive.generated.h"
+
+namespace CesiumGltf {
+struct Model;
+struct MeshPrimitive;
+} // namespace CesiumGltf
+
+/**
+ * Data that is common to the Cesium mesh component classes.
+ */
+class CesiumPrimitiveData {
+public:
+  /**
+   * Represents the primitive's EXT_mesh_features extension.
+   */
+  FCesiumPrimitiveFeatures Features;
+  /**
+   * Represents the primitive's EXT_structural_metadata extension.
+   */
+  FCesiumPrimitiveMetadata Metadata;
+
+  /**
+   * The encoded representation of the primitive's EXT_mesh_features extension.
+   */
+  CesiumEncodedFeaturesMetadata::EncodedPrimitiveFeatures EncodedFeatures;
+  /**
+   * The encoded representation of the primitive's EXT_structural_metadata
+   * extension.
+   */
+  CesiumEncodedFeaturesMetadata::EncodedPrimitiveMetadata EncodedMetadata;
+
+  PRAGMA_DISABLE_DEPRECATION_WARNINGS
+  /**
+   * For backwards compatibility with the EXT_feature_metadata implementation.
+   */
+  FCesiumMetadataPrimitive Metadata_DEPRECATED;
+
+  std::optional<CesiumEncodedMetadataUtility::EncodedMetadataPrimitive>
+      EncodedMetadata_DEPRECATED;
+  PRAGMA_ENABLE_DEPRECATION_WARNINGS
+
+  ACesium3DTileset* pTilesetActor = nullptr;
+  const CesiumGltf::Model* pModel = nullptr;
+  const CesiumGltf::MeshPrimitive* pMeshPrimitive = nullptr;
+
+  /**
+   * The double-precision transformation matrix for this glTF node.
+   */
+  glm::dmat4x4 HighPrecisionNodeTransform;
+
+  /**
+   * Maps an overlay texture coordinate ID to the index of the corresponding
+   * texture coordinates in the mesh's UVs array.
+   */
+  OverlayTextureCoordinateIDMap overlayTextureCoordinateIDToUVIndex;
+
+  /**
+   * Maps the accessor index in a glTF to its corresponding texture coordinate
+   * index in the Unreal mesh. The -1 key is reserved for implicit feature IDs
+   * (in other words, the vertex index).
+   */
+  std::unordered_map<int32_t, uint32_t> GltfToUnrealTexCoordMap;
+
+  /**
+   * Maps texture coordinate set indices in a glTF to AccessorViews. This stores
+   * accessor views on texture coordinate sets that will be used by feature ID
+   * textures or property textures for picking.
+   */
+  std::unordered_map<int32_t, CesiumGltf::TexCoordAccessorType>
+      TexCoordAccessorMap;
+
+  /**
+   * The position accessor of the glTF primitive. This is used for computing
+   * the UV at a hit location on a primitive, and is safer to access than the
+   * mesh's RenderData.
+   */
+  CesiumGltf::AccessorView<FVector3f> PositionAccessor;
+
+  /**
+   * The index accessor of the glTF primitive, if one is specified. This is used
+   * for computing the UV at a hit location on a primitive.
+   */
+  CesiumGltf::IndexAccessorType IndexAccessor;
+
+  std::optional<Cesium3DTilesSelection::BoundingVolume> boundingVolume;
+
+  /**
+   * The factor by which the positions in the glTF primitive is scaled up when
+   * the Unreal mesh is populated.
+   *
+   * We scale up the meshes because Chaos has a degenerate triangle epsilon test
+   * in `TriangleMeshImplicitObject.cpp` that is almost laughably too eager.
+   * Perhaps it would be fine if our meshes actually used units of centimeters
+   * like UE, but they usually use meters instead. With a factor of 1.0, UE will
+   * consider a right triangle that is slightly less than ~10cm on each side to
+   * be degenerate.
+   *
+   * This value should be a power-of-two so the the scale affects only the
+   * exponent of coordinate values, not the mantissa, in order to reduce the
+   * chances of losing precision.
+   */
+  static constexpr double positionScaleFactor = 1024.0;
+
+  void destroy();
+};
+
+UINTERFACE()
+class UCesiumPrimitive : public UInterface {
+  GENERATED_BODY()
+};
+
+/**
+ * Common interface to Cesium data and functions for Cesium Components.
+ *
+ * The Cesium component classes inherit from different classes in the Unreal
+ * Component hierarchy, so a multiple inheritance interface approach is needed
+ * to access their common data. Other ad-hoc functions are added to increase
+ * code reuse and make certain functions (e.g., UpdateTransformFromCesium())
+ * simpler.
+ */
+class ICesiumPrimitive {
+  GENERATED_BODY()
+public:
+  virtual CesiumPrimitiveData& getPrimitiveData() = 0;
+  virtual const CesiumPrimitiveData& getPrimitiveData() const = 0;
+
+  virtual void
+  UpdateTransformFromCesium(const glm::dmat4& CesiumToUnrealTransform) = 0;
+};